Gearing



' March 5, 1940; s, GREEN 2,192,188

GEARING Filed March 13, '1936 2 Sheets-Sheet 1 Inventor Samuel 5'. Green AHDFTLEJ March 1940- s. G. GREEN 2,192,188

GEARING Filed March 13, 1936 2 Sheets-Sheet 2 v 26 20 /9 Inventmr 5 amuel G -E r e 1' 2y MM Attm n ey h r aaim UNITED STATES PATENT OFFICE GEARING I I I Samuel (3.. Green, Gray, Ga. v I Application March 13, 1936,,Serial No. 68,690

I 7 Claims. (0114-440) (Granted under the act of March-.3, 1883, as q I amended April 30, 1928; 370 0. G- 757) v I I The invention described herein may be manuspectively provided with aligned annular re- I'actured and used by or for the Government for cess'es. Ill and II for receiving a spring 12.

governmental purposes, without the payment to: The scr'ew'is mountedon a driving shaft I3, me of any royalty thereon. the part 5being fixedthereto by a pin Hand 5 a This invention'relates to gearing. i the part 6 being slidable thereon so that it is 5 The purpose of this invention is to provide an I free tofmove axially relative to the fixed part. arrangement of reversible gearing for takingnp A collar 15 on -"the shaft limits the movement of clearance wherein a constant driving ratio is ,the part B to a very small amount. maintained without changing the pitch line or In Fig.5 theinvention is'shown as applied'to distance between the centers of the gears. gearing in 'the'form of a nut or internal screw 10 This is accomplished by dividing a pinion into C having two parts l6 and i1, respectively protwo parts with overlapping and interengaging visited with interengagingclutch fingers l8 and clutch fingers on which-a continuous thread is l9. Springs 20-40 confined between the parts, cut. I I U act to normally tend to separate the parts. A

To these and other ends, the'-invention con continuous thread?! cut-on the internal wall of '15",

sists in the construction, arrangement and com-- the nutengages the thread 22 ofa screw shaft bination of elements described hereinafter and or intermeshing element 23-. Ribs 24'and 25 repointed out in the claims forming a part of this spectively on the parts it and l! are engaged specification. I II in the groove 26 of a supporting member to hold 2 A practical embodiment of the invention is the'nut against rotation. t

illustrated in theaccompanying drawings; whereltwill be noted that the fingers or clutch members I and 8' preferablyhave a length to ac- Y Fig.- 1 is a longitudinalsectiona'l view, with commodate three-threads and constitute the maparts in elevation, of the improved gearing. jor threaded portionand also that their width Fig. 2 is a view in side elevation of the pinion: isso related to the gear wheel B that the threads 25'" with the parts separated. I r t 1 of at least two adjacent clutch members of each Fig. 3 ma view in side elevationwith the par p fi 6 w be Capable of Simultaneously assembled. I meshing with the gear wheel.

Fig. 4 is an end View of one of the parts. I claim: I I 30 Fig. 5 is a longitudinal sectional'view showing 1.=In an assembly of a reversible screw d 30'"- the application of the invention to gearing in intermeshing.element'incombination, a scr form Of a, nut. member comprising a pair of relative axially In the preferred embodiment of the invention movable parts including -'comp1emental interenshown in Figs. 1.4, there is shown helicalgeara g mt m m mutually overlapping ing comprising a pinion or screw A and an inter-- su-filcientlyto hear one or'more pitches of thread meshing element or gear wheel B. 'The screw portions formed thereon, said cl t h members A is formed of two parts 5 and 6 each having a having thread portions formed thereon to proplurality f sp d fi e or clutch members vide in their normal positions a continuous respectively designated 1 and 8, and adapted to thread of substantially uniform cross-section 40 Overlap aflli gage when the parts are traversing said members one or more revolutions, 40 brought together. a means interposed between said 'parts operable A thread -9 is cut in the screw with the parts I to effect relativeaxial movement thereof, an elein assembled relation and closely adjoining so 'ment disposed in meshing relation with the screw that the working thread portions on the interthread and. meshing with one or more pitches engaged fingers, in the normal position of the thereof, and said meshing element and clutch 45 latter, form a continuous thread of substantially I members being so related that the meshing eleuniform cross section. The threads are preferment will always mesh with the thread portions ably coextensive with the fingers although they of at least two opposed clutch members; wheremay extend beyond the bases of the fingers. by clearance between the thread and mesh ng Some form of pressure means,- of hydraulic, member may be reduced in the driving direction 50 pneumatic or spring, type, or a combination of without throwing the working thrust therebethese elements is employed to act on the parts tween on a thread portion of reduced-cross-sec- 5 and 6' and normally tend to move them with tion or changing the driving ratio. I relation to each other. As an example, in Fig. 1, 2. In a reversible screw and gear assembly n I the meeting faces of the parts 5 and 6' arerecombination, a screw member comprising a pair 5 of relative axially movable parts including complemental interengaging clutch members mutually overlapping suificiently to bear a plurality of pitches of thread portions formed thereon, said clutch members having thread portions formed thereon to provide in their normal positions a continuous thread of substantially uniform crosssection traversing said members. a plurality of revolutions, means interposed between said parts operable to effect relative axial movement thereof, a gear disposed in meshing relation with the screw thread and having a circular pitch adapting its teeth to be drivingly engaged by said thread through at least three pitches,i-and said gear and clutch members being sov related in width that the gear teeth will always engage the thread portions of at least two opposed clutch members; whereby clearance between the thread and gear teeth may be reduced in the. driving, direction without throwing the working thrust therebetween on a thread portion of reduced cross-section or, changing the driving ratio.

3. In a screw and gear assembly in combination, a screw member comprising a pair'of relative axially movable parts including complemental interengaging clutchmembers having formed thereon thread portionswhich in the normal position of said clutch members constitute a continuous thread of substantially uniform cross-section traversing the members at least one revolution, means interposed between said parts operable to effect relative axial movement thereof, and a gear having teeth engaging said thread, whereby driving contact between ;said screw and gear may be maintained in the driving direction without throwing the working thrust between said thread and gear teeth on a thread portion ofreduced cross-section.

4. In an assembly of the class described in combination, a shaft journaled for rotation, a screw.

member comprising a pair of generally cylindrical relative axially movable parts including complemental interengaging clutch vmembers mutually overlapping sufficiently to bear at. least one revolution of a v thread formed thereon mounted on said shaft with one part fixed thereto and the other part slidable thereon, said clutch members in their normal positions having threadportions formed thereon to provide a continuous thread of substantially uniform cross-section through at least one revolution, means interposed between said parts operable to eifect relative axial movement thereof, a gear disposed in meshing relation with said screw thread'and being so related in size with respect thereto as to always intermesh with the thread portions on at least' two opposed clutch members; whereby clearance between the threadand intermeshing gear may be reduced in the driving direction without throwing the working. thrust therebe tween on a thread portion of reduced cross-section or changing the driving ratio, and means forrotating said shaft.

5. In a screw and nut assembly in combination,

a nut member comprising a pair of relative axially movable parts including complemental interengaging clutch members mutually overlapping sufliciently to bear a plurality of revolutions of a continuous thread, said clutch members in their normal positions being formed with. internal thread portions arranged to providea continuous section extending through a pluralityof revolutions, means interposed between said parts oper-l able to effect relative axial movement thereof,

and a reversible screw disposed in meshing relation with said internal screw whereby clearance between the intermeshing thread portions may be reduced in the driving direction without internal thread of substantially uniform CIOSS-i members in their normal positions being formed. 7

to provide a continuous thread of substantially uniform cross-section extending through said plurality of pitches, and means interposed between said parts normally tending to efiect' axial separation thereof.

'7. In a compensating screw in combination; a

screw member comprising a pair of opposed generally cylindrical relative axially movable parts havingon their confronting portions a plurality of complemental interengaging' clutch members mutuallyoverla-pping a plurality of pitches .of a

thread formed thereon, said parts being formed interiorly to provide opposed aligned recesses, said clutch members being formed to provide in their normal positions a continuous thread of substantially uniform cross-section extending through said plurality of pitches, and spring means disposed in said opposed aligned recesses biased to normally effect axial separation of the said parts.

SAMUEL G. GREEN. 

